Blenders are kitchen appliances which are designed for mixing or blending food ingredients such as fruit, milk and ice, into liquids. Blenders typically consist of a base, having a vertically positioned powerful a/c motor with a lower coupling, and a cylindrical jar located directly above the base. The jar has a rotatable blade assembly at the bottom with an upper coupling driven by the lower coupling. The blade assembly is usually mounted in a blade-holding component which forms the bottom of the jar with a water tight seal in between, and removable for easy cleaning.
The blending performance of a blender is usually measured by the fineness of blended food ingredients after a limited time of blending. Critical for good performance of a blender is the diameter of the jar at blade height, but also the presence of turbulence-creating ribs of similar formations inside the jar, for example at blade assembly height. Such rib formations reduce spinning of liquid inside the jar, which thus enhances blending performance.
For hygiene, cleaning and durability reasons, blenders usually have jar made of glass material.
An example of a known blender 100 is depicted in FIG. 1. It comprises a base part 101 and a jar 102 made of glass arranged on the base part 101. The bottom part of the jar 102 is closed by a detachable bottom part 103. A sealing gasket 104 is disposed between the detachable bottom part 103 and the jar 102. The jar 102 comprises ribs 105 extending upwards on the inside surface of the jar 102. The ribs 105 are made of glass and are moulded together with the wall of the jar 102. A blade assembly 106 is disposed on the bottom part 103 and rotated by a motor assembly 107 disposed in the base part 101.
When manufacturing a jar made of glass, to facilitate the manufacturing, it is preferred that the geometry is cylindrical and uniform, without large protruding ribs inside the jar. This creates a dilemma since the very same ribs are critical to obtain good blending performance. The width of the ribs can be reduced to facilitate the moulding during manufacturing, but to the detriment of blending performance.